如何在不使用<链接href>导入bs css的情况下在stackblitz.com中使用ngx-bootstrap？

"styles": [
  "node_modules/bootstrap/dist/css/bootstrap.min.css",
  "src/styles.css"
]

import { ModalModule } from 'ngx-bootstrap/modal';
import { PopoverModule } from 'ngx-bootstrap/popover';

@NgModule({
  imports: [
    BrowserModule,
    ModalModule.forRoot(),
    PopoverModule.forRoot(),
    // 其他已有的模块
  ],
  // 其他配置项
})

import { BsModalService, BsModalRef } from 'ngx-bootstrap/modal';

constructor(private modalService: BsModalService) {}

openModal(template: TemplateRef<any>) {
  this.modalRef = this.modalService.show(template);
}

<button (click)="openModal(template)">打开模态框</button>

<ng-template #template>
  <div class="modal-header">
    <h4 class="modal-title">模态框标题</h4>
    <button type="button" class="close" aria-label="Close" (click)="modalRef.hide()">
      <span aria-hidden="true">&times;</span>
    </button>
  </div>
  <div class="modal-body">
    模态框内容
  </div>
</ng-template>

npm install ngx-bootstrap bootstrap